Reorganized core/ directory, it was too fatty already

-Removed FuncRef, since Callable makes it obsolete
-Removed int_types.h as its obsolete in c++11+
-Changed color names code

modules/gdscript/language_server/gdscript_text_document.h

@@ -31,8 +31,8 @@
 #ifndef GDSCRIPT_TEXT_DOCUMENT_H
 #define GDSCRIPT_TEXT_DOCUMENT_H
 
+#include "core/object/reference.h"
 #include "core/os/file_access.h"
-#include "core/reference.h"
 #include "lsp.hpp"
 
 class GDScriptTextDocument : public Reference {